EFFECTS OF ARG-GLY-ASP-SER ON CA2-RETICULUM IN RAT SEPTIC SHOCK( TRANSPORT OF MYOCARDIAL SARCOPLASMIC)

AIM: To study the effects of Arg-Gly-Asp-Ser (RGDS), a synthetic short peptide of fibrinogen degradation, on the Ca2+ transport function of cardiac sarcoplasmic reticulum in rat septic shock. METHODS: RGDS 5 mu mol . kg(-1) was injected iv at 4 h and 14 h after cecal ligation and puncture (CLP) operation on rats. Highly purified membrane of sarcopl asmic reticulum (SR) was prepared from rat hearts. Assays were made of ATP-dependent Ca2+ uptake by cardiac SR and [H-3] ryanodine binding t o SR. RESULTS: The initial rate and the capacity of SR Ca2+ uptake wer e increased by 104% (P<0.01) and 12% (P< 0.05), respectively, parallel ed by an increase in Ca2+-ATPase activity and a decrease in calcium ac cumulation of myo- cardium of septic rats, whereas the B-max and K-d v alues of Ca2+ activated [H-3]ryanodine binding to SR were unaffected a fter RGDS administration. CONCLUTIONS: The results indicated that RGDS have cardioprotective effects of maintaining Ca2+ homeostasis of card iac myocytes by enhancing SR Ca2+ uptake in rat septic shock.